The present invention relates generally to the structure and use of surgical instruments and, more particularly, to positionable support structures for manipulating parts of the body in surgical procedures.
Laparoscopic surgery is generally performed through small incisions in the abdomen using specialized instruments to accomplish the desired surgical procedure. Usually, the instruments are introduced through a narrow diameter tube, such as a trocar sleeve, while the physician observes manipulation of the instruments through specialized imaging equipment, such as a laparoscope. Laparoscopic surgical techniques offer significant advantages over conventional "open" surgical procedures. In particular, the laparoscopic techniques are usually less traumatic, require a shorter recovery time, and are less costly than corresponding conventional surgical procedures.
In laparoscopic surgical procedures, it is generally necessary to lift the abdominal wall away from the underlying abdominal organs to improve the visibility and accessibility of such organs. Such distension of the abdominal cavity, or peritoneum, has been heretofore accomplished by injecting a gas such as CO.sub.2 into the peritoneal cavity to tent-up the interior of the abdominal wall. Such "insufflation" requires gas seals to be present at all entry ports through the abdominal wall; and, because of the doming effect on the abdomen, the laparoscopic instruments (graspers, scissors, electrocautery instruments, etc.) need long shafts (on the order of 12"-13") to reach the treatment site. Such instruments are difficult to control and result in exaggerated movements during instrument application. Further, using the insufflation technique, maintenance of the required distension is complicated by the loss of gas through the entry ports through the abdominal wall.
It has been proposed to use a mechanical system for peritoneal distension to overcome the problems associated with the insufflation technique. For example, co-pending U.S. application Ser. No. 07/706,781, filed May 29, 1991, entitled "Apparatus and Method for Peritoneal Retraction," the full disclosure of which is incorporated herein by reference, describes a technique for lifting the abdominal wall by means of angle-shaped rods having elongated arms at their distal ends which are inserted through an incision and fanned out within the abdomen. A mechanical lifting arm mounted to the surgical table is positioned over the patient and coupled to the rods, and lifting is accomplished by activating a motor in the arm. Such mechanical systems must be readily manipulable by the treating physician. In particular, such a mechanical lifting arm must be (1) horizontally positionable over the desired site, and (2) vertically adjustable to raise the abdominal wall in a controlled manner.
For these reasons, it would be desirable to provide improved methods and apparatus for mechanical manipulation of body structures, particularly for distending the peritoneal cavity during laparoscopic surgical procedures. In particular, the methods and apparatus should provide for controlled lifting of the abdominal wall or other body structure, preferably using power-assisted lifting and lowering. The methods and apparatus should allow manipulation of body structures by a single person, and should be simple to operate. The apparatus should have convenient controls, preferably located in the immediate vicinity of the surgical working area, most desirably immediately above the working area. The methods and apparatus should further have application in surgical facilities not equipped with pneumatic or hydraulic supply lines, and should provide for patient and operator safety in the event of a power failure. It would also be particularly desirable if the methods and apparatus were suitable for performing manipulation of body structures other than the peritoneum in other types of surgical procedures.